Over the past 20 years, obesity rates in U.S. children and youth have skyrocketed. National studies show that disparities exist where racial/ethnic minorities and those from a low-income are at higher risk for being overweight or obese. Design, implementation and dissemination of effective school-based prevention programs are critical to addressing these disparities in the obesity epidemic, however few successful models exist. Interventions that are both informed by community partners using a CBPR approach and are comprehensive, and those that include the integration of individual (physical activity behaviors), social (PE teacher curriculum training activities) and environmental (improved school PE equipment) factors have greater success in achieving long-term effects on children's obesity-related behaviors and cognitive performance, especially among medically underserved areas/populations (MUA/P). Resulting from a partnership with the UCLA School of Nursing, the Los Angeles Unified School District (LAUSD) we propose to assess the impact of a middle-school based environmental and curriculum intervention on physical activity and fitness behaviors and standardized achievement test scores among MUA/P youth. This research also examines whether the effects of the intervention vary by gender and ethnicity. The proposed environment and curriculum, coordinated school health program will consist of three components: (1) the SPARK Middle School Physical Education and Nutrition (M-SPAN) Program, 2) professional development (PD) and curriculum training for PE teachers; and 3) provision of quality PE equipment. This study uses a cluster randomized controlled trial design at 24 MUA/P middle schools in the LAUSD with repeated measures (pre-program, mid-program, immediate post-program) and random assignment to the intervention. M-SPAN is an evidenced-based program and is recommended by the CDC to decrease childhood obesity. In order to enhance M-SPAN, SPARK has created PE equipment to match the activities in M-SPAN. The curriculum intervention entails the combination of SPARK Active Recreation and LAUSD PE Standards curricula and will be delivered once a month over 11 months of each of the two intervention years (total 22 months). The project design will be implemented in two waves. Wave I (with 6 sites from each study condition) will run from Years 1-3 and Wave II (with 6 sites from each study condition); will run from Years 2-4. The study aims will be evaluated with objective and subjective activity measures including SOPLAY (System for Observing Plan and Leisure Activity in Youth), physical fitness via the FitnessGram assessment, measured by body composition (decreased BMI and skinfold thickness), aerobic fitness (one mile run), and muscular strength/endurance (curl-up and pull-up) as well as standardized achievement test scores. A small subsample of youth from intervention schools (n=3,960) will also be assessed for physical activity via a modified Youth Risk Behavior Survey (YRBSS), pre-intervention, mid- intervention and immediate post-intervention. For Wave I years 1, 2, and 3 and for Wave II, years 2, 3 and 4.